Special Right Triangles

I'm not understanding too well. I would really appreciate an explanation. I answered what I could (which isn't much at all). All the ones I did not answer, I would really appreciate an explanation as to how to solve them.

If you have a 45-45-90 triangle:

1. And the length of one leg is 3, what is the length of the other leg? - Answer: AA 3 B 6 C9 D12 E 15 F 18

2. With a hypotenuse of SQRT(6), what is the length of one leg? A sqrt 81 Bsqrt 3 Csqrt 12 Dsqrt 23 E sqrt 37 F sqrt 42

3. And one leg has a length of 5, what is the length of the hypotenuse? - Answer: FA 2sqrt3 B6sqrt4 C7sqrt9 D9sqrt7 E 4sqrt5 F 5sqrt2

4. With a hypotenuse of 7[SQRT(2)], what is the length of one leg? - Answer: 7A 12 B94 C22 D7 E 45 F 2

5. With a hypotenuse of 6[SQRT(6)], what is the length of one leg? A 6 sqrt(3) or 10.3923 B4 sqrt(10) or 9.3156 C3 sqrt(4) or 2.5631 D1 sqrt(5) or 3.5941 E 2 sqrt(9) or 8.2145 F 8 sqrt(7) or 6.2211

6. And one leg has a length of SQRT(8), what is the length of the hypotenuse? A 12 B9 C4 D18 E 26 F 2

7. And one leg has a length of SQRT(32), what is the length of the hypotenuse? A 24 B8 C46 D12 E 65 F 34

8. With a hypotenuse of SQRT(3), what is the length of one leg? A 1.225 B2.189 C7.641 D1.218 E 4.321 F 1.657

9. With a hypotenuse of 6, what is the length of one leg?

A 11sqrt3 B4sqrt7 C7sqrt8 D3sqrt2 E 8sqrt9 F 2sqrt5

10. And one leg has a length of 7[SQRT(72)] what is the length of the hypotenuse? A 04 B48 C91 D84 E 75 F 23